Mechanically assisted spiral-draft water-cooling tower

ABSTRACT

A forced-draft cooling tower employs fans, passages to receive fan-displaced air or gas, and packing sections spaced about the tower axis so that positive swirling of the gas or air about that axis within the tower interior is produced as the flow passes through the passages and packing sections.

United States Patent 1 1 esa/3 [72] lnventor Donn B. Furlong [56]References Cited 2| A I N 2 Califunmzo STATES PATENTS I I 86 A 61,739,867 12 1929 Seymour 261/79 A I22] Med Oct. 15, 1969 1,865,2456/1932 Goodloem 55/484 X [45) Patented Sept. 28, 1971 [73] AssigneeFluor Products Com an Inc 1929A 10/1933 Cosy 4 261/79 A Santa Rosa Cam P2,732,190 1/1956 Mart H 261/21 3,290,867 12/1966 Jacir 261/D1G. 113,400,917 9/1968 Richards 26l/D1G. 11

Primary Examiner-Tim R. Miles [54] MECHANICALLY ASSISTED SPHRALDRAFTAttorneys-White and Haefliger and Charles M. Kaplan WATER-COOLING TOWERl8 Clams 8 Drawmg Flgs' ABSTRACT: A forced-draft cooling tower employsfans, [52] U.S. Cl 261/30, passages to receive fan-displaced air or gas,and packing sec- 261/79 A, 261/] 1 1, 261/DIG. 1 1 tions spaced aboutthe tower axis so that positive swirling of [51] Int. Cl 1801f 3/04 thegas or air about that axis within the tower interior is [50] Field ofSearch 261/79 A, produced as the flow passes through the passages andpacking DlGi11,108-113, 24, 30

sections.

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INVENTO/Q DOA/N B IMeLoA/G MECHANICALLY ASSISTED SPIRAL-DRAFT WATER-COOLING TOWER BACKGROUND OF THE INVENTION This invention relatesgenerally to mechanical and natural draft watencooling towers, and morespecifically concerns an unusually advantageous and economical towerconstruction with substantially increased water-cooling capacity.

Conventional mechanical and natural draft towers typically employ griddecking or packing for draining and splashing water in such dispersedcondition as to be cooled by air streams passing generally horizontallythrough the packing. The packing decks normally extend continuouslyalong the side or sides of such a tower in order to achieve directinward flow through the packing of all air passing between the exteriorand interior of the tower, this having been thought to be consistentwith most economical tower construction and mode of operation. Forexample, it was thought that continuity of packing extent along thetower sides achieves maximum surface to area ratio, the surfacereferring to available wetted packing area presented to the enteringair, and area referring to the ground area covered by the tower.

It has been found, however, that the construction and operation ofconventional mechanical-draft towers present certain problems and lackof desired economies. For example, the length of packed sections islimited to the length of the tower side, limiting the water-coolingcapacity of the tower below desired level; also, where fans were locatedoutside the tower, the amount of packing was reduced by virtue of thelocation of individual packing sections adjacent the discharge sides ofthe fans, resulting in unequal airflow into the packing sections, atendency to icing of the fans in cold weather due to water-dropletsplash, and unused gaps between the packing sections as in US. Pat. No.2,732,190 to Mart.

BRIEF SUMMARY OF THE INVENTION It is a major object to provide amechanical or natural draft tower construction such as will overcome theabove-referredto problems, as well as others, while at the same timeproviding unusual advantages contributing to reduction in space occupiedby a tower of given capacity, production of spiral flow of air into thetower interior and a gain in tower-operating economy. Basically, theinvention is embodied in a tower construction that includes a series offans spaced about and outwardly of the tower upright axis; plenumpassages spaced about that axis and in the path of gas displacement bythe fans; multiple packing sections spaced about the axis and located inthe spaces between the passages for inlet exposure to the passages andoutlet exposure to the tower interior; partitions to direct the flow ofgas into the packing sections after gas reception in the passages sothat the resultant flow swirls about the tower axis, and means to supplywater (or other liquid) for dispersal within the sections to be cooledby the gas flow therethrough. As a result, the passages act to equalizethe fan-discharge flow to the packing sections, and also to isolate thefans from water splash near the packing, to prevent fan icing. Also, thestructure enables housing of dampers, doors or similar devices forregulating airflow into the tower as required for cold-weatheroperation. The tower shell may be of right circular cylindrical,hyperboloid of revolution or other geometrically regular form.

Typically, the tower construction may include certain upright partitionsextending within the spaces between the packing sections to confine theair to enter the sections at the inlet sides and to flow laterallywithin the sections, such partitions for example extending diagonallybetween the outer extents of the outlet sides of the sections and theinner extents of the inlet sides of the sections to effect the spiralflow. As will be seen, the fans are typically mounted at the towerperiphery outwardly of the spaces between the packing sections to directairflow toward the diagonal partitions. Further, the tower constructionmay include other partitions covering the outermost and innermostextents of the packed sections.

Additional objects and advantages of the invention include the provisionof fan shrouds extending with gas-directing diffusing divergence fromthe fan peripheries toward adjacent packing sections; the provision ofpacking sections circularly arranged about a vertical central axis withsection elongation generally radially; the provision of vanes in thepassages or spaces between the packing sections and angled to guide thefan-displaced gas flow into the packing sections; the provision forinlet flow of air to the plenum passages in bypassing relation to thefans when the latter are shut down, to enable natural-draft mode oftower operation; the provision of watersupply means including a waterbasin overlying the section and spaces therebetween, the basin havingdispersal openings located only over the sections; the provision ofmeans including piping having water outlets direct-ed to discharge waterinto the basin to flow therealong and over the sections and spacestherebetween; and the provision of a basin underlying such spaces toreceive water splashing into the spaces from the packing sections.Conventional natural'draft cooling tower, usually of hyperboloidal shapedepend largely upon the lesser density of the moisture laden interiorair than ambient air to create the draft or air movement. During ambientatmospheric conditions unfavorable to the creation of sufficient draftfor desired cooling performance; the present invention on the other handprovides auxiliary fans to create the needed air movement (quantity). Ina similar manner, the addition of fans can reduce the design size of thecooling tower where available site area is limited.

These and other objects and advantages of the invention, as well as thedetails of illustrative embodiments, will be more fully understood fromthe following specification and drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational showing ofone form of mechanicaldraft tower incorporating the invention;

FIG. 2 is a fragmentary plan view of a portion of the FIG. I tower, andpartly broken away to show interior construction;

FIG. 3 is an enlarged elevation taken in section on line 33 of FIG. 2;

FIG. 4 is an enlarged elevation taken on line 4-4 of FIG. 2;

FIG. 5 is an enlarged elevation taken on line 55 of FIG. 2;

FIG. 6 is an enlargedelevation taken on line 6-6 of FIG. 2;

FIG. 7 is a schematic plan view of a modified form of the invention; and

FIG. 8 is another schematic plan view of a further modified form of theinvention.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIGS. 1-6, theillustrated water-cooling tower is of mechanical-draft type, wherein airis displaced horizontally into the lower interior of the tower and risesin the stack ill of vertical cylindrical shape and defining a centralaxis 10a. The stack has modular panel construction, as shown, and iscircular in horizontal planes as is the annular lower portion 12 of thetower. While airflow to cool dispersed water is described, it will beunderstood that gas flow to cool liquid is comprehended within the scopeof the invention.

Included in the tower is a plurality of water-receiving packing sectionshaving inlet and outlet sides laterally separated in a directiongenerally lengthwise or circumferentially of the tower horizontalperiphery. As seen in FIG.

2, the sections 13 are typically rectangular in plan view with inlet andoutlet sides 13a and 13b separated in the circumferential direction.Further, the sections 13 are circularly arranged about the verticalcentral axis llia of the tower, with spacing therebetween indicated at Mfor reception of air between the sections. Air displaced into thesespaces, or plenum passages 14a then turns to flow through the sections13 between sides 13a and 13b, and is subsequently received in spaces 14bfor exit flow to the tower interior I00. Arrows I5 designate the generalflow path. As is clear from FIG. 2, the

flow through the sections 13 has a substantial component 15a concentricwith the (circumferential) direction of the tower horizontal periphery,and the resultant flow into the tower interior and about axis 10aproduces a swirl effect. The latter upward spiral course of the positiveflow induces enhanced mixing of the moisture-laden air or gas, so as todecrease the density thereof in order to increase the tendency of theair to rise in the tower. The airflow may typically approach aturbulent-flow state, permitting increased air-water contact withconsequent raising of the wet bulb temperature of the exit air, therebyimproving the water-cooling performance.

Certain partitions or control baffles extend within the plenum passages14 to direct the air to enter the sections 13 at their inlet sides, toflow laterally therein as described. For example, vertical partitions 16may be provided to extend diagonally between the outer extents 17 of theoutlet sides 13b of the sections 13 and the inner extents 18 of theinlet sides 13a of the sections. Further, other vertical partitions 19and 20 are provided to cover the outermost and innermost extents of thesections 13. Such partitions may extend throughout the vertical heightsof the sections 13 to block airflow through those inner and outerextents or ends.

Typically, the like sections 13 are radially horizontally elongated andthe overall radial dimension of the section multiplied by the number ofsuch sections substantially exceeds the boundary dimension (as forexample circumference of tower lower portion 12) defined by the outerextents of the sections. Accordingly, a substantially higher than normalratio of surface to area" is achieved, these terms having beenpreviously defined.

Extending the description to FIGS. and 6 fans 30 are spaced in circularseries about axis a and radially outwardly therefrom, the fans alsobeing spaced outwardly of the plenum passages 14a and oriented topositively displace air into those spaces when the fans are rotated bymotor 31. Accordingly, the fans are kept well away from the sections 13to prevent icing of the blades due to water splash in cold weather.Also, flow of air into the sections is equalized by the plenum passages.In this regard, the fans have blades 32 and may be housed in suchrelation to passages 14a that air may freely flow past the fans and intothose passages when the fans are shut down, providing an auxiliarynatural-draft mode of tower operation as may be desirable or effectiveunder certain weather condition. For example, the spaces 33 between theblades may pass such airflow, or alternatively the fan housing mayprovide for such bypass flow. The fan motors 31 may be supported onstands 34 having legs 34a and a crosspiece 34b as shown.

Housing of the fans 30 may be effected by means of shrouds 35 havingventuri shape, forming throats 36 receiving the fans and diffusersections 37 to expand the flow to the full vertical flow area of theplenum chambers. The shrouds may, for this purpose be verticallyelongated as seen in FIG. 5, and extend with divergence to tops andbottoms 38 and 39 of the passage opening, and to the vertical sides 40and 41 thereof.

FIG. 7 illustrates the use of additional flow guides such as vanes 44 inpassages 14a, and angled to direct the fandischarge flow uniformly intothe packing sections. Dampers may be used to regulate the inlet airflow,as during coldweather operations. See, for example, dampers 75 movablein shroud 35 in FIG. 8, as by pivoting at 76.

Referring back to FIGS. 14, means is provided to supply liquid, as forexample water, for distribution within the sections in order to becooled by airflow through the latter, the water typically falling indispersed drops which splash and film on the decking surfaces or slats.Many different types of decking or fill may be used, FIG. 4 indicating aclosely packed section 13 of such fill as inclined downwardly and in thedirection airflow through the fill, water particles tending to fall inthe packing with corresponding angularity from vertical. Tower structuresupporting the fill includes columns 55, ties 56 and bracing 57. Anupright drift eliminator 58 is spaced close to the outlet side 13b ofthe packing for eliminating drift particle form the exit air stream.

The water supply means illustrated in the drawings includes a hot waterbasin 60 overlying the packing sections 13 and the spaces 14a and 14btherebetween. As seen in FIG. 3, hot water may be pumped from a concretesupply conduit 62 upwardly within a riser 62 to a flume or piping 63extending transversely and and inwardly across the basin 60. The latterhas multiple outlets 64, individually valve controlled at 65, directedto discharge water into the basin for open-channel flow therealong inthe length direction of the basin. The basin has intermittent groups 66of distribution openings 67 located lengthwise thereof, for dispersingwater into and onto the decking or packing sections 13; also the basinover the spaces 14 between sections 13 is free of such holes so thatwater does not drain from the basin into the interiors of those airspaces. On the other hand, any water splashing from the packing into thespaces 14 falls into the collection basin 69 at the bottom of the tower,and no louvers are needed to intercept such splash since spaces 14 arewithin the tower.

To complete the description, an access walkway is shown at 71 over thepiping 63; walkway 72 extends along and at the inner side of the basin60.

I claim:

1. In a mechanical-draft-liquid cooling tower having an upright axis,the combination comprising a. a series of fans spaced about andoutwardly from said axis,

b. means defining a series of plenum passages spaced about said axis andin the direct path of gas displacement by the fans, toward the towerinterior,

c. multiple packing sections spaced about said axis and located in thespaces between said passages, said sections having inlet exposure to thepassages and outlets communicating with the tower interior,

d. said means including generally upright partitions to direct thefan-displaced gas into said packing sections after reception of the gasin said passages, and with directional flow components angled from saidaxis so that the gas upon exiting from said sections flows in an upwardspiral course about said axis within the tower interior, said partitionsextending within the plenum passages, and

e. means to supply liquid for dispersal within said sections to becooled by the gas flow therethrough 2. ln a mechanical-draft coolingtower having a generally circular horizontal cross section and avertical axis, the combination comprising,

a. a plurality of upright generally annularly spaced packing sectionshaving open inlet and outlet sides laterally separated in a directiongenerally lengthwise of the tower periphery, the sections being spacedin said direction and about said axis for reception of gas therebetweenprior and subsequent to gas flow through the sections between said sidesso that the flow through the sections has substantial componentsparallel to said direction, the sections also being radially outwardlyspaced from said direction, the sections also being radially outwardlyspaced from said axis,

b. certain upright partitions located in said spaces between thesections and extending generally diagonally between the outer extents ofsaid outlet sides of the sections and the inner extents of the inletsides of the sections, thereby to direct the gas to flow in a spiralcourse about said vertical axis as the gas passes through the sectionsand into the tower interior inwardly of said sections, there being otherpartitions located at the radially inner and outer ends of the sectionsto block airflow therethrough,

c. multiple fans mounted to discharge gas under pressure into saidspaces at the inlet sides of the sections for forced-draft flow throughthe sections, and

d. means to supply liquid for dispersal within said sections to becooled by the gas flow therethrough, said flow in a spiral courseinducing enhanced mixing of the moistureladen gas so as to decrease thedensity thereof thereby to increase the tendency of the gas to rise inthe tower.

3. The combination of claim 2 wherein said fans are mounted at the towerperiphery to direct said discharge gas toward the diagonal partitions.

4. The combination of claim 3 including fan shroud each extending withgas-diffusing divergence from the fan peripheries toward the adjacentpacking section.

5. The combination of claim 4 wherein said shrouds are verticallyelongated.

6. The combination of claim 4 wherein the fans are located directlyoutwardly of spaces.

7. The combination of claim 3 including vertically elongated vaneslocated in said spaces radially inwardly of the fans and angled to guidethe gas flow into said sections.

8. The combination of claim 1 wherein the fans have blades and arehoused in such relation to said passages that gas may flow past the fansinto said passages when the fans are shut down.

9. The combination of claim 4 including damper means mounted formovement within at least one shroud for regulating inlet airflow.

l0. ln a natural-draft liquid-cooling tower having an upright axis, thecombination comprising a. a series of fans spaced about and outwardlyfrom said axis,

b. means defining a series of plenum passages spaced about said axis andin the direct path of gas displacement by the fans, toward the towerinterior,

c. multiple packing sections spaced about said axis and located in thespaces between said passages, said sections having inlet exposure to thepassages and outlet communicating with the tower interior,

(1. said means including generally upright partitions to direct thefan-displaced gas into said packing sections after reception of the gasin said passages, and with directionalflow components angled from saidaxis so that the gas upon exiting from said sections flows in an upwardspiral course about said axis within the tower interior, said partitionsextending within the plenum passages, and

e. means to supply liquid for dispersal within said sections to becooled by the gas flow therethrough.

11. In a natural-draft cooling tower having a generally circularhorizontal cross section and a vertical axis, the combinationcomprising,

a. a plurality of upright generally annularly spaced packing sectionshaving open inlet and outlet sides laterally separated in a directiongenerally lengthwise of the tower periphery, the sections being spacedin said direction and about said axis for reception of gas therebetweenprior and subsequent to gas flow though the sections between said sidesto that the flow through the sections has substantial componentsparallel to said direction, the sections also being radially outwardlyspaced from said axis,

b. certain upright partitions located in said spaces between thesections and extending generally diagonally between the outer extents ofsaid outlet sides of the sections and the inner extents of the inletsides of the sections, thereby to direct the gas to flow in a spiralcourse about said vcrtical axis as the gas passes through the sectionsand into the tower interior inwardly of said sections, there being otherpartitions located at the radially inner and outer ends of the sectionsto block airflow therethrough,

c. multiple fans mounted to discharge gas under pressure into saidspaces at the inlet sides of the sections for forced-draft flow throughthe sections, and

d. means to supply liquid for dispersal within said sections to becooled by the gas flow therethrough, said flow in a spiral courseinducing enhanced mixing of the mositureladen gas so as to decrease thedensity thereof thereby to increase the tendency of the gas to rise inthe tower.

12. The combination of claim 11 wherein said fans are mounted at thetower periphery to direct said discharge gas toward the dia onalpartitions.

13. The com ination of claim l2 including fan shrouds each extendingwith gas-diffusing divergence from the fan peripheries toward theadjacent packing sections.

14. The combination of claim 13 wherein said shrouds are verticallyelongated.

15. The combination of claim 13 wherein the fans are located directlyoutwardly of said spaces.

16. The combination of claim 12 including vertically elongated vaneslocated in said spaces radially inwardly of the fans and angled to guidethe gas flow into said sections.

17. The combination of claim 10 wherein the fans have blades and arehoused in such relation. to said passages that gas may flow past thefans into said passages when the fans are shut down.

18. The combination of claim 13 including damper means mounted formovement within at least one shroud for regulating inlet airflow.

1. In a mechanical-draft liquid-cooling tower having an upright axis,the combination comprising a. a series of fans spaced about andoutwardly from said axis, b. means defining a series of plenum passagesspaced about said axis and in the direct path of gas displacement by thefans, toward the tower interior, c. multiple packing sections spacedabout said axis and located in the spaces between said passages, saidsections having inlet exposure to the passages and outlets communicatingwith the tower interior, d. said means including generally uprightpartitions to direct the fan-displaced gas into said packing sectionsafter reception of the gas in said passages, and with directional flowcomponents angled from said axis so that the gas upon exiting from saidsections flows in an upward spiral course about said axis within thetower interior, said partitions extending within the plenum passages,and e. means to supply liquid for dispersal within said sections to becooled by the gas flow therethrough
 2. In a mechanical-draft coolingtower having a generally circular horizontal cross section and avertical axis, the combination comprising, a. a plurality of uprightgenerally annularly spaced packing sections having open inlet and outletsides laterally separated in a direction generally lengthwise of thetower periphery, the sections being spaced in said direction and aboutsaid axis for reception of gas therebetween prior and subsequent to gasflow through the sections between said sides so that the flow throughthe sections has substantial components parallel to said direction, thesections also being radially outwardly spaced from said direction, thesections also being radially outwardly spaced from said axis, b. certainupright partitions located in said spaces between the sections andextending generally diagonally between the outer extents of said outletsides of the sections and the inner extents of the inlet sides of thesections, thereby to direct the gas to flow in a spiral course aboutsaid vertical axis as the gas passes through the sections and into thetower interior inwardly of said sections, there being other partitionslocated at the radially inner and outer ends of the sections to blockairflow therethrough, c. multiple fans mounted to discharge gas underpressure into said spaces at the inlet sides of the sections forforced-draft flow through the sections, and d. means to supply liquidfor dispersal within said sections to be cooled by the gas flowtherethrough, said flow in a spiral course inducing enhanced mixing ofthe moisture-laden gas so as to decrease the density thereof thereby toincrease the tendency of the gas to rise in the tower.
 3. Thecombination of claim 2 wherein said fans are mounted at the towerperiphery to direct said discharge gas toward the diagonal partitions.4. The combination of claim 3 including fan shroud each extending withgas-diffusing divergence from the fan peripheries toward the adjacentpacking section.
 5. The combination of claim 4 wherein said shrouds arevertically elongated.
 6. The combination of claim 4 wherein the fans arelocated directly outwardly of said spaces.
 7. The combination of claim 3including vertically elongated vanes located in said spaces radiallyinwardly of the fans and angled to guide the gas flow into saidsections.
 8. The combination of claim 1 wherein the fans have blades andare housed in such relation to said passages that gas may flow past thefans into said passages when the fans are shut down.
 9. The combinationof claim 4 including damper means mounted for movement within at leastone shroud for regulating inlet airflow.
 10. In a natural-draftliquid-cooling tower having an upright axis, the combination comprisinga. a series of fans spaced about and outwardly from said axis, b. meansdefining a series of plenum passages spaced about said axis and in thedirect path of gas displacement by the fans, toward the tower interior,c. multiple packing sections spaced about said axis and located in thespaces between said passages, said sections having inlet exposure to thepassages and outlet communicating with the tower interior, d. said meansincluding generally upright partitions to direct the fan-displaced gasinto said packing sections after reception of the gas in said passages,and with directional-flow components angled from said axis so that thegas upon exiting from said sections flows in an upward spiral courseabout said axis within the tower interior, said partitions extendingwithin the plenum passages, and e. means to supply liquid for dispersalwithin said sections to be cooled by the gas flow therethrough.
 11. In anatural-draft cooling tower having a generally circular horizontal crosssection and a vertical axis, the combination comprising, a. a pluralityof upright generally annularly spaced packing sections having open inletand outlet sides laterally separated in a direction generally lengthwiseof the tower periphery, the sections being spaced in said direction andabout said axis for reception of gas therebetween prior and subsequentto gas flow though the sections between said sides to that the flowthrough the sections has substantial components parallel to saiddirection, the sections also being radially outwardly spaced from saidaxis, b. certain upright partitions located in said spaces between thesections and extending generally diagonally between the outer extents ofsaid outlet sides of the sections and the inner extents of the inletsides of the sections, thereby to direct the gas to flow in a spiralcourse about said vertical axis as the gas passes through the sectionsand into the tower interior inwardly of said sections, there being otherpartitions located at the radially inner and outer ends of the sectionsto block airflow therethrough, c. multiple fans mounted to discharge gasunder pressure into said spaces at the inlet sides of the sections forforced-draft flow through the sections, and d. means to supply liquidfor dispersal within said sections to be cooled by the gas flowtherethrough, said flow in a spiral course inducing enhanced mixing ofthe moisture-laden gas so as to decrease the density thereof thereby toincrease the tendency of the gas to rise in the tower.
 12. Thecombination of claim 11 wherein said fans are mounted at the towerperiphery to direct said discharge gas toward the diagonal partitions.13. The combination of claim 12 including fan shrouds each extendingwith gas-diffusing divergence from the fan peripheries toward theadjacent packing sections.
 14. The combination of claim 13 wherein saidshrouds are vertically elongated.
 15. The combination of claim 13wherein the fans are located directly outwardly of said spaces.
 16. Thecombination of claim 12 including vertically elongated vanes located insaid spaces radially inwardly of the fans and angled to guide the gasflow into said sections.
 17. The combination of claim 10 wherein thefans have blades and are housed in such relation to said passages thatgas may flow past the fans into said passages when the fans are shutdown.
 18. The combination of claim 13 including damper means mounted formovement within at least one shroud for regulating inlet airflow.